Method and apparatus for pressing fibrous materials having entrained fluids



June 7, 1966 c. GARRow ETAL METHOD AND APPARATUS FOR PRESSING FIBROUSMATERIALS HAVING ENTRAINED FLUIDS 2 Sheets-Shea?l 1 Filed April e, 1962June 7, 1965 c. GARROW ETAL METHOD AND APPARATUS FOR PRESSING FIBROUSMATERIALS HAVING ENTRAINED FLUIDS 2 Sheets-Sheet 2 Filed April 6, 1962United States Patent O Claims priority, 'application Australia, Apr. 14,1961, 3,580/ 61 2 Claims. (Cl. 53-24) This invention relates to animproved process for pressing fibrous materials having entrained fluids,materials such as wool and other natural and synthetic fibrous materialsare normally lofty and have a lot of air and, in some cases moisture,entrained with the fibres and are normally baled for transport and/ orstorage.

When handling such materials, `for example raw wool in a shearing shed,one of the most arduous operations performed is normally that ofpressing the wool into bales. Pressing involves initially stamping ortramping wool into a jute bale arranged in a press box followed lby amechanical pressing of the wool in the bale. It is, of course, desirableto produce uniform bales but in practice the size, Weight and shape `ofthe resultant bale depends greatly upon the efficiency of the wool pressused and the care taken by the operator during loading wool into thepress.

Considerable -savings in transport and handling costs could be eifectedif such lrbales were of uniform size, weight and shape. It is well knownthat the density of bales varies considerably. A survey conducted someyears ago showed that a bale pressed in the standard wool press has -onan average a density of about 12l1bs. per cubic foot. A dumped bale,that is after further hydraulic pressing for export was found to have anaverage density of 15.9 lbs. per cubic foot. However, it was also foundthat individual bale densities varied considerably about the average.

Other requirements for the packing and transport of wool are theprevention of contamination of wool by jute fibres from the pack .andmaintenance of a fairly constant water content dur-ing transport andstorage. In the case of Wool, the need for maintaining constant watercontent arises from the practice of selling wool by weight.

Somewhat similar considerations apply to the packing and transport ofother materials such as other natural fibres and artificial fibres.

Accordingly, it is an object of the present invention to provide animproved method for packing materials such as wool or other fibrousmaterial for baling.

It is also a further and subsidiary object of the invention to provide amethod and means for maintaining substantially constant the moisturecontent of fibrous material which has been baled.

According to this invention there is provided a method \of pressingiibrous materials having entrained fluids which comprises the steps offeeding the material to be pressed into a ilexible container which issubstantially uid tight and which is capable of reduction in volume.evacuating fluid from the container and causing or perc ICC mitting thecontainer to reduce its volume under the influence of -atmosphericpressure and thereby to compress the material, and inserting the packagethereby formed into a restraining envelope of greater size than thecompressed package. y

The restraining envelope, which may be a jute sack, is of a desired sizeand shape and fluid is again admitted to the container so that thematerial may again partly expand and assume the shape and size of therestraining envelope. The envelope can, of course, be of -any desiredshape or material. Alternatively, or in addition, the final shape andrestraint may be provided by means other than an envelope. For example,the container may be bound by steel -bands or wires. The flexiblecontainer may initially be supported by a rigid housing structureadapted to impart a preferred shape to the material during compression.

. The invention also includes apparatus for carrying out the abovemethod. The apparatus comprises essentially a substantially fluid tightcontainer which is capable of reduction in volume under the influence ofatmospheric pressure and means to evacuate fluid from the container.

It will be appreciated that whilst the method and apparatus of thisinvention is intended primarily to eifect compression of the material bythe action of Iatmospheric pressure on an evacuated container, otheradditional pressures, such as mechanical pressures may, if desired, beapplied to assist in the process. j

In order that the invention may be more fully understood, referegncewill now be made to certain practical embodiments used for the pressingof raw wool which will be described with reference to the accompanyingdrawings. In the drawings:

FIGURE 1 is a cross-sectional view of a form of apparatus for carryingout the invention using a flexible container within a rigid housing,

FIGURE 2 is a perspective view of the apparatus of FIGURE i1 in thecondition where the compression has [been completed and the container ofcompressed Wool is hoisted on a wheeled gantry ready for discharge fromthe the housing and insertion into a jute sack, and

FIGURE 3 is a detailed side elevation, partly in section, of -apreferred form of suction pipe which is used for vevacuating air fromthe exi-ble container and which is also adapted for use as the meanswhereby the container of compressed wool may be lifted.

The apparatus shown in FIGURES l to 3 comprises essentially a metal bin1, about half of which is let into the oor 2 of a wool store, shearingshed or the like in which the pressing is to be done. Placed'within thebin and forming a lining to it is a flexible airtight container 3 whichmay conveniently be a bag made of polyethylene film. The top of the bagis lapped over the -top of the bin and is held in position on the bin bymeans of some sort of binding such as a rubber ring 4. One side 5 of thebin is hinged at floor level Iby a hinge 6 which enables that side ofthe bin to be folded down when necessary. In the closed position theside 5 is held in position by means of pins 7 (see FIGURE 2). FIGURE 3shows an evacuating pipe 8 which is connected to some suitable knownevacuating means such as an evacuating pump not shown). The pipe 8 is ofspecial construction. Over approximately its lower half it is perforatedas shown at 9 to provide holes through which air may be sucked. At the`bottom of the pipe there is a retractable projection 10 pivoted -at 11to one side of the pipe. Connected to the projection is a connecting rod12 which extends up through the pipe to a cranked shaft 13 mounted inthe pipe at yright angles to its longitudinal axis and having a handle14 which projects outside the pipe. By manipulation of the handle 14 theprojection 10 may be brought to the position shown in FIGURE 3 whereinit iis as right angles to the axis of the pipe or to an inoperativeposition in which it is substantially parallel to the axis of the pipe.

In operation, with the container in the bin, the suction pipe 8 with theprojection 10 in its operative position (shown in FIGURE 3) is loweredinto the bin and then Wool is loaded into the container until it isalmost filled. The dimensions of the bin and container are such that thecapacity of the container is approximately three times the volume towhich the material will ultimately be compressed. When the container isfilled to the desired height the rubber ring is released and the top ofthe bag is folded around the suction pipe by some convenient means suchas another smaller band 15 (see FIGURE 3). The vacuum pump is thenstarted and air is sucked out of the container through the perforations9 and as the container is evacuated atmospheric pressure acting upon itsWalls compresses the material within the container until, after aconsiderable degree of compression is obtained, the evacuating isterminated or if necessary reduced to an equilibrium value with anyleakage which may be tak1ng place. ably supported over the bin. by meansof a block and tackle 16 supported by a wheeled gantry'17.

After the compression is completed the suction pipe 1s hauled up byhauling on the tackle rope 18 and because the wool is tightly packedaround the pipe and because of the engagement between the projection 10and the Wool the package of compressed wool is hauled up on the pipe.Hauling is continued until the compressed package of Wool is containedwithin the upper portion of the bin and the hinged side of the bin isthen folded down. The gantry is wheeled out and the compressed packageof wool is taken clear of the bin. At this stage the compressed packagemay be subjected to the final restraining means which will be usedduring its storage and transport. These may be for example steel bandsor a conventional jute sack. Where a jute sack is used the compressedpackage of wool (which has been compressed to a volume smaller than thatof the sack) is inserted into the sack. The projection on the suctionpipe is then retracted to its inoperative position parallel to the axisof the pipe and the pipe may then be Withdrawn from the package. Theneck of the bag is maintained sealed by any convenient means which maybe the ring 15. -The flaps of the jute sack are then closed inconventional manner and may be secured by conventional securing meanssuch as wire bale fasteners. At this stage air is readmitted to theinner polyethylene container by any suitable means, for example bypuncturing the wall of the container and as the air is readmitted thepackage expands so as to fill the jute sack and to assume the shape ofthe sack.

It will be noted that the walls of the bin converge slightly in thedownward direction. It has been found that in the pressing of wool usingan ordinary straightsided bin the resultant package produced afterevacuation tended to be of greater area at the base than towards the topand this led to some difliculties in subsequent placement of thecompressed package within the jute sack and in obtaining a package whichwould readily assume the shape of the sack. It is believed that thistendency may be related to the compression of the lower portions of thewool under the weight of the wool above it and accordingly the bin wasshaped as shown in order to counteract this tendency.

It is considered that the above described pressing tech- During thisoperation the suction pipe is prefernique has several advantages overthe conventional wool pressing operations at present in use. There isfirst of all the fact that a good deal of the hard work of initiallytramping a load of Wool into a sack mounted within a press box and thestraining required to close the flaps of a sack which is subjected tothe internal pressure of the compressed wool is eliminated. Further andmore substantial advantages are derived from the fact that it ispossible by the above described technique to produce a bale of wool ofwhich the size, weight and density may be more accurately controlled.Furthermore, it provides a simple means whereby a jute bale of Wool maybe provided with an inner liner of inert material such as polyethylenefilm, polyvinylacetate film, regenerated cellulose film or othersuitable material which will protect the wool from contamination by thejute of the sack. A further advantage arises out of the fact that theinner container is impervious to water and this substantially protectsthe Wool from moisture contamination and from substantial fluctuation inthe moisture content of the Wool. A still further advantage arises outof the fact that the apparatus required is less complex and lessexpensive to construct than conventional pressing apparatus and asaforementioned is easier and less arduous to manipulate.

Furthermore, it is believed that this apparatus possesses the advantagethat pressing is carried out under more favourable conditions than inconventional presses. In accordance with this invention the pressing iseffected at sub-atmospheric pressures. In conventional presses thecompression is at pressures which are super-atmospheric. It is believedthat the evacuation of air entrained in the wool leads to more efficientpressing and leads to the attainment of a predetermined degree ofpressing with the performance of a lesser amount of work.

The above embodiment of the invention has been described by way ofillustration of how the fundamentally new concept of pressing accordingto this invention can be carried into effect. Y It must be realised,however, that this embodiment is merely exemplary and although theinvention has been illustrated by reference to the production of balesof wool which are substantially conventional in size and in shape and inthe materials used it must be fully understood that the application ofthe invention is not limited by these considerations. Indeed it isbelieved that the invention may give rise to the opportunity forfundamental departures from present concepts of pressing and packing forstorage and transport.

We claim:

1. A method of pressing and baling fibrous materials having entrainedfluids. which comprises the steps of feeding the material to be pressedinto a flexible container which is substantially fluid tight and whichis capable of reduction in volume, evacuating fluid from the containerand permitting the container toreduce its volume under the influence ofatmospheric pressure and thereby to compress the material, enclosing thecontainer and its enclosed material in a restraining envelope of greatersize than the container with the compressed material therein, and thenreadmitting air to the container while the latter remains enclosed insaid envelope so as to permit the material to expand against and assumethe shape and size.

of said restraining envelope.

2. In apparatus for compressing fibrous materials containing entrainedfluids within a flexible fluid-tight container, the combination of arigid housing structure for supporting the flexible container during thecharging of the fibrous material into the container, and means toevacuated fluid from the. container, said housing structure havingdownwardly convergent side walls whereby, upon the evacuation of thefluids from the container, a substantially parallel-sided package isproduced, said evacuating means including a perforated pipe adapted tobe embedded in the material and which has at its lower end a retractableprojection which acts as a hook to per- 5 6 mit the packed container tobe lifted by means of the tube 2,564,969 8/ 1951 Goldberg. at thecompletion of the compression. 2,640,342 6/ 1953 Rand 100-37 ReferencesCited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 5 223,044 7/1959 Australia.

773,876 11/ 1904 Lorillard 100-40 X 1,406,380 2/1922 Heath et al 53 22TRAVIS S- MCGEHEE, Prlmdfy Exammef- 2,057,121 10/ 1936 Trevellyan 53- 24ABRAHAM G. STONE, FRANK E. BAILEY, 2,225,810 12/ 1940 Waters 53-22 XExaminers. 2,241,943 5/ 1941 Befh 53-22 10 L. o. MAASSEL, AssistantExaminer.

2,368,624 2/ 1945 Walton 53-112

1. A METHOD OF PRESSING AND BALING FIBROUS MATERIALS HAVING ENTRAINEDFLUIDS WHICH COMPRISES THE STEPS OF FEEDING THE MATERIAL TO BE PRESSEDINTO A FLEXIBLE CONTAINER WHICH IS SUBSTANTIALLY FLUID TIGHT AND WHICHIS CAPABLE OF REDUCTION IN VOLUME, EVACUATING FLUID FROM THE CONTAINERAND PERMITTING THE CONTAINER TO REDUCE ITS VOLUME UNDER THE INFLUENCE OFATMOSPHERIC PRESSURE AND THEREBY TO COMPRESS THE MATERIAL, ENCLOSING THECONTAINER AND ITS ENCLOSED MATERIAL IN A RESTRAINING ENVELOPE OF GREATERSIZE THAN THE CONTAINER WITH THE COMPRESSED MATERIAL THEREIN, AND THENREADMITTING AIR TO THE CONTAINER WHILE THE LATTER REMAINS ENCLOSED INSAID ENVELOPE SO AS TO PERMIT THE MATERIAL TO EXPAND AGAINST AND ASSUMETHE SHAPE AND SIZE OF SAID RESTRAINING ENVELOPE.